BULK GASES & SYSTEMS TECHNICAL CONTENT

Fossil fuels. Are they detrimental to the environment? Are they past their prime? Is hydrogen what we should be talking about? Are there other technologies that should be capturing our attention?

Heat Treat Today and our good friends at heatprocessing, Europe’s leading heat treat magazine, sought outstanding U.S. and European experts in the energy field to answer and provide analysis about the state of natural gas and hydrogen combustion. This original content piece, edited by Karen Gantzer, managing editor at Heat Treat Today, appeared in the Heat Treat Today 2020 Medical & Energy December print edition. We hope you enjoy this Technical Tuesday.

The following article highlights the insight of seven gentlemen in the heat treating industry, from both the U.S. and Europe, who work within the energy sector. We asked them for their responses to three questions regarding natural gas and hydrogen combustion. Our European colleagues also commented on whether hydrogen will be an important

factor in the heat treat industry in 10 years. There is a diversity of opinions among the experts, and it’s important to note how regional economics and resources may have impacted responses.

We hope you enjoy the analysis from our experts.

Where do you see the natural gas industry today? Where do you believe it will be in 10 years?

John B. Clarke, technical director at Helios Electric Corporation, a combustion consultancy in Fort Wayne, Indiana, shares how different his answer would have been if asked years ago about the state of natural gas: “Had you asked me 25 years ago, I would have described a market with a declining supply of natural gas resulting in rising costs. A market dominated by a drive to increase efficiency to control energy costs. That was then, but now we have an abundant (yet finite) supply of natural gas resulting in very low costs – and in the medium term, a market dominated by a drive to reduce emissions. Increased efficiency – both in the medium term and today – will reduce energy costs while at the same time reduce CO2 emissions.”

Clarke continues, “Given the prevalence of hydraulic fracturing, we can expect an expanding availability of natural gas, if the market price provides a sufficient return for the producers. The greatest disruption in the natural gas market will likely be on the consumption side as electrical power producers continue their shift away from coal to natural gas. While renewables will play a larger part, they cannot meet the requirement to provide continuous base load power to consumers.”

Dave Wolff, region sales manager at Nel Hydrogen, a manufacturer of onsite hydrogen generation, agrees with Clarke on the budget friendly price of natural gas, and he also cautions that it’s a finite resource: “It is an amazing time to be a natural gas user. Natural gas has never been cheaper than it is today ($2.00/MMBTU range). But the super low pricing won’t last forever. It is critical to understand that natural gas reserves are a finite resource, and that at today’s pricing, most shale operations are losing money. The Energy Information Association (EIA) expects that natural gas pricing will go up 50% in 2021 versus 2020.”

Regarding the future, Wolff recommends, “. . . wind and solar energy are truly infinite energy sources. Unlike the volatile and unpredictable natural gas pricing chart, renewable electricity prices are on a steady downward trend... So, I would strongly advise people to test their investment decisions as to the varying picture for natural gas versus electric price predictions. Especially if buying furnaces, this is critical, since the lifetime cost of a furnace is overwhelmingly a function of energy.”

Keenan Cokain, global sales and applications coordinator and Michael Cochran, an applications engineer, both from Pittsburgh’s Bloom Engineering, an industrial combustion and controls company, add another consideration: “Natural gas is a vital primary energy source globally and will likely remain so over the next 10 years. Although energy demands will likely show an overall decline in 2020, over the next 10 years, global natural gas consumption will likely rise as it continues to grow in comparison to other fossil fuels (such as oil and coal) as a percentage of the global primary energy consumed.

"It is important to note that when combusted natural gas (methane) produces about 117 lbs. of carbon dioxide (CO2) per 1 million Btu released, this is lower than oil and coal which produces 164 lbs. and 208 lbs. of CO2 per 1 million Btu respectively. Given the fact that natural gas produces lower CO2 emissions compared to other common fossil fuels, some see it as a bridge fuel that could be used in greater amounts until other fuel sources with lower carbon dioxide footprints are developed."

Do our European colleagues share a similar view?

Dipl.-Ing. Gerd Waning, market development in Metallurgy Heat Treatment at Linde GmbH, a global industrial gases and engineering company, states, “Due to the excellently developed natural gas infrastructure in many European countries, natural gas is today probably the best established energy source in industry and households with a high level of acceptance in terms of environmental friendliness and safety.”

In regard to decarbonization, the removal of hydrocarbons from combustion, Waning shares, “In connection with the strongly accelerated decarbonization of industrial and energy production in Europe, it can be assumed that the share of natural gas in the overall energy business will initially increase through 2030. The scheduled shutdown of coal and nuclear power plants (in Germany) will not be able to be compensated by renewable energy sources during this period, so the deficits in the in-house production of electricity will have to be partially compensated by natural gas.”

Dr.-Ing. Michael Severin, business field manager, Process Heat, at Karl Dungs GmbH & Co. KG, a supplier for combustion controls components and system solutions for heating burners, boilers, process heat, and gas engines, introduces climate-neutrality and digitalization to the conversation. “The natural gas industry, with its conservative requirements, is challenged by modern demands for climate-neutrality and digitalization. I believe in 10 years we will have proven that combustion and climate-neutrality are not contradictory, and that safety and security can be boosted by intelligent systems. However, in 10 years these examples will still be pilot projects, with a growing infrastructure and the broad transition happening gradually.”

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Lars Böhmer, managing director at the Research Association for Industrial Furnace Construction (FOGI) within VDMA Metallurgy, a joint platform of metallurgical machinery producers in Europe, believes the changes that are coming are necessary and will not be a surprise to the natural gas industry. “So, all stakeholders, suppliers as well as users, are in dialogue regarding possible solutions,” explains Böhmer.

Regarding the future, Böhmer states, “The market in 10 years’ time will certainly be a different one than today, and you don’t have to be a prophet to say that alternative fuels will play a greater role than they are currently. Whether these alternative fuels will then be used 100% or as a blend may well depend on many regional, but also technical, parameters.”

What do you perceive to be the eventual move from fossil fuels to hydrogen-based fuels? Why the move away from fossil fuels?

There is a consensus among our experts that reducing carbon dioxide emissions is a universal desire and that the burden to accomplish this goal lies within countries around the world. What is fascinating are the various options they provide to replace the carbon-based fuels.

Cokain and Cochran, from Bloom Engineering, share their thoughts on generating hydrogen on an industrial scale and viable next steps. They say, “The most common way to generate hydrogen today on an industrial scale is through a process called steam-methane reforming. During this process natural gas (methane) and steam are combined under pressure with catalysts in a twostep process to produce carbon dioxide (CO2) and hydrogen (H2). Once the carbon dioxide is removed, one is left with pure hydrogen that can be used as a carbon-free fuel source. The downside to steam-methane reforming is that by the time the steam is produced and the carbon stripped from the natural gas, the resulting carbon dioxide emissions can be on the order of 40% more per unit of fuel energy produced than would have resulted from the direct combustion of natural gas. This means that without being coupled with carbon capture and store (CCS) – capturing the CO2 before it leaves the plant – a move to hydrogen based fuels generated using today’s most common methods of hydrogen production would result in an increase of carbon dioxide emissions into the atmosphere.”

The Bloom team continues, “Other methods of producing hydrogen that would not result in increased generation of carbon dioxide are currently being developed. One such method would be electrolysis or the use of electricity to decompose water into hydrogen and oxygen. If the electric for such a process were generated using renewable or ‘carbon neutral’ sources, then the carbon penalty associated with hydrogen production could be eliminated.”

Nel Hydrogen’s Wolff contends, “It seems straightforward that forever energy sources are going to be less expensive in the long run than finite ones. No matter what your environmental politics, the facts are that finite resources go up in price as supply shrinks relative to demand.”

“Hydrogen for the heat treat industry is unlikely to be used as a fuel – it is used as an atmosphere component, with diluents such as nitrogen or argon, and with carbon-contributors such as methanol or even methane itself,” Wolff continues. “Long-term, we at Nel expect that hydrogen produced on-site will be the predominant hydrogen-containing atmosphere approach.”

Clarke of Helios Electrical Corporation is a believer in battery technology, “The movement from coal to natural gas is, in essence, a move from full carbon to a carbon/hydrogen fuel. As for pure hydrogen fuel cells, there may be new technology that drives the costs down, but my bet is that battery technology advancement will push fuel cells from most applications.”

While the economic impact on the infrastructure to build thousands of recharging stations will surely be a consideration for the future of electric cars, Clarke says, “I believe we will see an accelerated movement to electric vehicles. Battery technology has reached a point where the range of these vehicles are acceptable for an increasing number of consumers.” Clarke continues, “This will move consumption from gasoline and other petroleum- based fuels but may increase demand for natural gas for power generation.”

“In the end,” Clarke explains, “it always comes down to economics – cost of new equipment, cost of operating, and cost of regulation. I believe current users of fossil fuel heating equipment in the industry can expect the cost of equipment and regulations to increase. More efficient technology with heat recovery will cost more to purchase and install, and we can expect regulatory compliance costs to increase. As for cost of operating the equipment, I am optimistic that decreased energy consumption might offset increased energy costs.”

Karl Dungs GmbH & Co.’s Severin shares two options for transitioning to include hydrogen in a combustion system: “Hydrogen as a chemical energy carrier makes green electric power storable and utilizable for industries where large amounts of heat and high temperatures are required. Infrastructure and gas systems can be used with hydrogen with minor adaptations to the combustion system. For the transition, there are two possible ways. Either hydrogen is blended into natural gas networks and the ratio will be ramped up over the years. Or, parallel hydrogen networks will be created, which supply particular plants with 100% hydrogen now and will then grow and spread into the rest of the industry over the years. The determination between these scenarios is hard to foresee at the moment, but I personally see a trend towards the latter.”

Böhmer, of VDMA, knows there are field tests with fuel/gas mixtures containing 20% hydrogen, however he thinks we’ll see “an intermediate step of about 60% hydrogen, since there is little experience beyond this value. The question that plays a big role regarding this topic is, ‘How much hydrogen, which is produced by means of renewable energy, will be available at all?’”

Waning, from Linde GmbH, addresses the longevity of furnace systems and new systems versus conversions: “Due to the long service life of heat treatment systems, there will be only a few systems built exclusively for hydrogen as a heating medium. The technological feasibility of converting from natural gasfired systems to hydrogen-fired systems or a mixture of natural gas and hydrogen (50/50) is only just beginning to be researched on an industrial scale, whereas the conversion of the infrastructure to high hydrogen concentrations is considered manageable. However, this changeover should not be critical, particularly in the case of heat treatment systems that are fired with closed radiant heating tubes due to their protective atmosphere operation."

Should captive heat treaters be talking about hydrogen or are there other technologies they should be focusing on?

Linde GmbH’s Waning states that there are no significant differences between contract heat treaters and in-house heat treaters because of the comparable systems used by both. However, he does encourage us to focus on the period after 2023. He says, “Here it becomes clear how strongly development depends on current local political action. France, for example, continues to consistently focus on expanding the use of electricity. Here the heat treatment company is well advised to operate electrically heated systems if they want to minimize their CO2 footprint. Paired with nitrogen-methanol or hydrogen as a protective gas from green sources, a heat treatment process with the lowest CO2 emissions can be created.”

“In Germany,” Waning continues, “the picture is completely different. The move away from coal and nuclear power towards renewable energies led to the recently adopted German hydrogen strategy. There is no getting around the increasing use of hydrogen as a combustion medium, as the regulations for a massive expansion of the electrical networks in Germany lead to extremely long implementation times. While the same must be said here for the protective atmosphere side as for France and all other countries, the heat treatment company in Germany should consider being able to react flexibly to the actual conditions with hybrid heating (electric + gas).”

Severin, from Karl Dungs GmbH & Co., talks about biogas: “Biogas can have the same CO2 -neutral balance as hydrogen and has a better availability in many regions nowadays. However, biogas will always be a very limited resource and will not be able to serve a whole industry segment. Other climate-neutral fuels, like synthetic methane or higher hydrocarbons, always involve a loss in overall efficiency. In the long run, I only see hydrogen as a feasible and comprehensive solution for green combustion technology.”

VDMA’s Böhmer cautions against thinking that hydrogen is the silver bullet to solve the climate challenges: “In my opinion, considering hydrogen as the one and only solution to climate problems would be the wrong way to go. Hydrogen is one of several possible solutions, although it has already turned out to play a very important role against the background of the already mentioned storage possibilities of regeneratively produced energy. But it also has to be taken into account that the hydrogen, be it as combustion gas or as basis for further conversions, has to be available everywhere it is needed and in the required quantities.”

Böhmer also reminds us there are possible solutions in the world of synthetically produced fuels that are not exclusively hydrogen-based. In fact, “in the aviation industry, the use of sustainable kerosene from ‘power-to-liquid’ plants is not only being discussed but is already being tested. So, the fuel of the future does not necessarily have to be only gaseous, and actually there are many different approaches and efforts to reach the targets.”

To the heat treater, Böhmer emphasizes that electric heating, i.e., inductive hardening, “must not be missing. It can be assumed that the share of electrical heat treatment will increase, as the use of pure or blended hydrogen as fuel gas may be critical, depending on the process and material.”

Helios Electrical Corporation’s Clarke doesn’t believe hydrogen as a heating technology is a viable option. He says, “Obviously, hydrogen as an atmosphere will continue to be used. Burning hydrogen to generate heat is more problematic – heat transfer from the flame to the work being heated (or inside of a radiant tube) is a function of radiation and convection. The hydrogen flame will lack much of the luminosity we have come to expect when burning CH4. The change in luminosity will alter the heat transfer mechanism, providing greater heat flux over a smaller area. Hydrogen also has a very high flame propagation rate.” He mentions the cost of producing and transporting hydrogen must enter into the equation.

Clarke continues, “As an industry, we still have a great deal of energy that can be extracted from the exhaust products of natural gas-fired equipment.” Although he points out that “current economics make the deployment of more advanced technology to capture and reuse this heat unattractive in many cases,” he expects “the cost of natural gas and/or the demand of regulations may very well change this equation in the 10-year time frame.” (In North America, unfortunately, mandated regulatory compliance may be the only viable adaptation of this technology.)

One last opportunity that Clarke mentions is “the efficiency gains that result from improving equipment maintenance, adjusting fuel/air ratios to reduce excess air, cleaning heat transfer surfaces, and maintaining combustion chambers at the optimum pressure to decrease tramp air. Deploying new technology is like a football team hiring a star quarterback. He is not too valuable if the team ignores basic blocking and tackling.”

Bloom Engineering’s Cokain and Cochran think the response from captive heaters may very well be dictated by the area in which they do business, as discussed earlier. “In some places, the goal of reducing carbon dioxide emissions at the point of use could outweigh the fact that hydrogen generation, specifically using steam-methane reforming (SMR) which is most common today, often carries a carbon penalty and is more costly compared to the direct combustion of natural gas. Unless hydrogen production, specifically through SMR coupled with carbon capture and store (CCS), can be made more cost effective, heat treaters in these carbon-regulated areas may want to consider electrification if their process permits.”

They continue, “Unlike some other pollutants that have a largely localized effect, carbon dioxide (CO2) is expected to make the same contribution to global climate change regardless of where it is released. As a result, decarbonization regulations would need to be applied globally to be effective. Otherwise, heat processing industries will likely shift away from regulated regions due to the cost advantages of operating in unregulated areas and continue to add CO2 to the atmosphere.”

And lastly, the Bloom team advises this approach, “Today, the best way for captive heat treaters to minimize carbon dioxide emissions would be to maximize process efficiency and minimize energy use. In other words, burn less fuel and use less electric. For any process that relies on the combustion of fossil fuels, an increase in efficiency that results in a net reduction of fuel burned will proportionally reduce carbon dioxide emissions. One possible way to increase efficiency in a combustion process would be to recover heat from that process’s waste gases through the use of a recuperator or regenerative burner technology. These types of technologies can greatly increase efficiency, but they must be carefully applied since they are not compatible with all combustion processes.”

How important will hydrogen be for the heat treatment industry in 10 years?

Our European experts share their thoughts on the role of hydrogen in the heat treat industry in the next decade.

Waning of Linde GmbH suggests, “Many heat treatment processes that are currently operated with carbon-containing protective atmospheres could alternatively also be operated with very high hydrogen contents. From the current state of technological knowledge, it is mainly atmospheric carburization systems that require a significant proportion of carbon monoxide in the atmosphere in order to be able to operate economically. (Such processes can, however, also be operated with a low CO2 footprint if they are operated with nitrogenmethanol from renewable sources.)”

“Assuming a high availability of inexpensive hydrogen, many operators would opt for the protective gas with the higher hydrogen content, especially since this would result in other significant advantages in terms of furnace life and cleanliness of the systems and quenching medium,” states Waning. “On balance, it can therefore be assumed that in the future there will be a higher hydrogen demand in the heat treatment industry for the protective gas sector alone.”

Karl Dungs GmbH & Co.’s Severin responds, “This depends highly on the regional availability, national regulations, and subsidies. I see local ‘valleys’ of hydrogen grids, with the heat treatment industry being one of the drivers to demand a carbon-neutral energy source, where electrification is not possible. Cost is the main obstacle for this option, so cost reduction in international supply chains, infrastructure, and applications with large consumption is key. In 10 years, this won’t be achieved fully, and hydrogen solutions will still be more expensive than natural gas combustion.”

“Hydrogen will certainly play a greater role for the heat treatment industry than it does today,” states Böhmer, of VDMA. “Regardless of whether pure hydrogen, a natural gashydrogen blend or synthetic natural gas produced by methanization is used in the combustion processes; the fact is that hydrogen will play an important and decisive role as fuel-gas for combustion processes. In this context, the possibility of storing energy by means of hydrogen should not be forgotten in energy-intensive fields such as the heat treatment industry.”

Böhmer concludes, “Nevertheless, it also has to be taken into consideration that there may be a possible influence of hydrogen not only on the burner and the fuel supply regarding choice of materials and safety-procedures, but especially on the material to be treated. Therefore, a possible conversion of hydrogen into synthetic gases must be considered in some cases. It goes without saying that the efficiency and costs play a decisive role in this context.”

For more information, contact the experts:

1. John B. Clarke, Technical Director, Helios Electric Corporation: jclarke@helios-corp.com
2. Keenan Cokain Global Sales and Applications Coordinator, Bloom Engineering: kcokain@bloomeng.com
3. Michael Cochran, Applications Engineer, Bloom Engineering: mcochran@bloomeng.com
4. Dave Wolff, Region Sales Manager, Nel Hydrogen: dwolff@nelhydrogen.com
5. Dipl.-Ing. Gerd Waning, Market Development Metallurgy Heat Treatment, Linde GmbH: gerd.waning@linde.com
6. Dr.-Ing. Michael Severin, Business Field Manager Process Heat, Karl Dungs GmbH & Co. KG: m.severin@dungs.com
7. Lars Böhmer, Managing Director, Research Association for Industrial Furnace, Construction (FOGI) within VDMA Metallurgy: lars.boehmer@vdma.org